U.S. Pat. No. 3,603,134 issued Sept. 7, 1971 to one of the present inventors and is assigned to the same assignee. That patent discloses and claims a detector having a cell comprising a metal block defining sample and reference chambers for receiving the effluent and carrier gases, respectively, of a chromatographic column. Hot wire detectors are mounted in the gas flow stream passing through each chamber. The cell is surrounded by carrier gas for reducing gas leakage between surrounding atmosphere and the detector chambers. The detector contemplated by the present invention also finds application in CHN analyzers such as that disclosed in U.S. Pat. No. 3,698,869.